Olfactory dysfunction

• Assessing Taste and Smell Dysfunction in Acute and Chronic Stroke Patients: Insights From an Adapted Bedside Questionnaire
• The Development and Validation of the Smell-Qx Questionnaire, Based on a Systematic Review of the Literature and the COMET Initiative on the Development of Core Outcome Sets for Clinical Trials in Olfactory Disorders
• SG06, a Chalcone Derivative Targets PI3K/AKT1 Pathway for Neuroprotection and Cognitive Enhancement in an Alzheimer's Disease-Like Zebrafish Model
• The involvement of the cholinergic system in Parkinson disease
• Neural and vascular contributions to sensory impairments in a human alpha-synuclein transgenic mouse model of Parkinson's disease
• The risk of Long Covid symptoms: a systematic review and meta-analysis of controlled studies
• Neurological Post-Acute Sequelae of COVID-19 in Non-Hospitalized Patients: An Integrative Review
• Aging inhibits olfactory recovery from traumatic olfactory system injury

​Olfactory impairment (OI), or the diminished ability to smell, has been increasingly recognized as a significant predictor of mortality in older adults. This association persists even after accounting for factors such as age, cognitive function, depression, and comorbidities.​

Independent Predictor of Mortality: Studies have demonstrated that OI is a strong, independent predictor of mortality. For instance, a study published in PLOS ONE found that older adults with anosmia (complete loss of smell) had over three times the odds of death compared to those with normal olfactory function, even after adjusting for various health factors.

Association with Neurodegenerative Diseases: OI is often an early symptom of neurodegenerative diseases such as Alzheimer's and Parkinson's. A study in Frontiers in Public Health reported that OI was associated with a 43% higher risk of death over ten years, with the association being even stronger in individuals with neurodegenerative diseases.

Link to Frailty and Aging: OI has been linked to frailty and the aging process. Research suggests that olfactory dysfunction may reflect broader physiological decline, including reduced cellular regeneration and increased vulnerability to environmental hazards .

Impact on Nutrition and Safety: Impaired olfaction can lead to decreased appetite and poor nutrition, as well as an inability to detect hazardous situations like gas leaks or spoiled food. These factors can contribute to increased mortality risk .

Given these findings, assessing olfactory function in older adults could serve as a valuable tool for identifying individuals at higher risk of mortality. Objective smell tests may help in the early detection of underlying health issues, allowing for timely interventions.​

Olfactory dysfunction (OD), defined as the reduced or distorted ability to smell during sniffing (orthonasal olfaction) or eating (retronasal olfaction), is often reported in mild or even asymptomatic cases; in a study from Italy, 64% of 202 mildly symptomatic patients reported impaired olfaction.

see Anosmia after anterior communicating artery aneurysm surgery.